Re: Desoldering Iron vacuum
You don't have to take the pace vane pump apart. When the
vanes start to stick, just put the hose into a bottle of
99% IPA, and snorfle up the alcohol. Put a small hose on
the pressure output port so that you can run the waste
alcohol into a bottle for the next time. You can reuse
the alcohol a dozen times or more.
-Chuck Harris
Glenn Little wrote:
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The flux fumes will go right through the fiber disk.
I use a Pace desoldering system with a cotton like plug in the solder capture
cylinder and a fiber filter at the end of the tubing just before it goes into the
vacuum pump.
The fiber filter catches a lot but not all of the vapor.
A lot of the flux vapor condenses out onto the inside wall of the tubing connecting
the iron to the vacuum pump.
The installed vacuum pump here is a rotary vane pump.
About once a year, I have to disassemble the pump and clean the carbon vanes and the
carbon wear plates to remove the condensed flux vapor.
The amount of flux vapor ingested by the system is based on the amount of residual
flux left on the solder being removed and the length of time that you are sucking the
solder in one session.
The hotter the air through the system the more vaporized flux gets to the pump.
If you only remove a few parts then let the system rest and the solder capture
cylinder cool down there is less flux vapor than if you desolder a large quantity of
parts at one time.
I do the latter and have recovered over 20 pounds of solder from boards.
Glenn
On 7/29/2018 10:51 AM, John Griessen wrote:
On 07/29/2018 06:18 AM, Mark Wendt wrote:
The Hakko desoldering station I have has two sets of inline filters. One, a kind
of springy thingy for stopping the solder bits and pieces from flowing into the
pump, and the other a fiber disc for stopping the smokey stuff from getting
through. Perhaps on John's system the fiber disc isn't in place to stop that from
happening? It's in place. It's not enough though.
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Re: Desoldering Iron vacuum
On 07/29/2018 11:57 AM, Kevin Oconnor wrote: has an internal glass pass-thru tube with an S shape metal insert that congeals the solder and a cotton plug that trap vapors. If removed and cleared periodically, it works flawlessly. That's another data point saying a cold trap is good for long low maintenance. "S shape metal insert that congeals the solder" ==> cold-trap
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Re: Desoldering Iron vacuum
On 07/29/2018 11:02 AM, Glenn Little wrote: The fiber filter catches a lot but not all of the vapor.
A lot of the flux vapor condenses out onto the inside wall of the tubing connecting the iron to the vacuum pump. Yes, that is why I was suggesting a section of pipe with TP wads -- it would be a cold trap and a big wide filter, and it wouldn't have to be vacuum perfect since only intermittently pulled down. For an on-demand pump, the old Hakko 470 has a diaphragm pump with rubber reed valves and works pretty well, so it's not on my to do list yet. Strong vacuum from a reservoir and mini-fridge pump sounds better for good solder sucking. then the cold-trap-filter between iron and solenoid valve would be worth it.
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Re: Desoldering Iron vacuum
My Pace station desolder tool has an internal vac pump and the tool has an internal glass pass-thru tube with an S shape metal insert that congeals the solder and a cotton plug that trap vapors. If removed and cleared periodically, it works flawlessly.
Half dozen different tips makes desoldering a cakewalk usually.
Kevin
Sent from kjo iPhone
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Re: Replacing Electrolytics in a 465/465B
Another method that works well is to use individual adapter
boards for each cap. The boards are roughly the same diameter
as the original caps and allow a modern snap cap to be used.
You can make the patterns up in any drawing program if you want
to etch your own, gerbers are floating around the web and
they are available on ebay once in a while. The boards work
out to be around $1 or less each if you use one of the cheap board
houses.
If you use long leads on those, you can thread the cap in without
having to disassemble the scope.
That method seems to have been independently invented four or five
times that I'm aware of (and probably many more).
Paul
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-----Original Message-----
From: n4buq <n4buq@...>
To: TekScopes <[email protected]>
Sent: Wed, Jul 25, 2018 1:05 am
Subject: [TekScopes] Replacing Electrolytics in a 465/465B
Recently, I had a problem with the LV supplies in my 465B. Thinking it was a
shorted electrolytic can, I decided to replace all of them (although it
turned out to be a shorted tantalum but had already pulled the cans before
finding the real problem).
I decided to design a small PC board on which to mount modern snap-in caps.
THe board mounts with standoffs in the exising larger holes that are left
when the cans are removed and allow replacement of the snap-ins if/when they
fail and that can be done without further soldering on the original board.
Pictures of the board and the process are in the following album:
/g/TekScopes/album?id=64929 -- Paul Amaranth, GCIH | Rochester MI, USA Aurora Group, Inc. | Security, Systems & Software paul@... | Unix & Windows
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Re: Desoldering Iron vacuum
The flux fumes will go right through the fiber disk.
I use a Pace desoldering system with a cotton like plug in the solder capture cylinder and a fiber filter at the end of the tubing just before it goes into the vacuum pump.
The fiber filter catches a lot but not all of the vapor.
A lot of the flux vapor condenses out onto the inside wall of the tubing connecting the iron to the vacuum pump.
The installed vacuum pump here is a rotary vane pump.
About once a year, I have to disassemble the pump and clean the carbon vanes and the carbon wear plates to remove the condensed flux vapor.
The amount of flux vapor ingested by the system is based on the amount of residual flux left on the solder being removed and the length of time that you are sucking the solder in one session.
The hotter the air through the system the more vaporized flux gets to the pump.
If you only remove a few parts then let the system rest and the solder capture cylinder cool down there is less flux vapor than if you desolder a large quantity of parts at one time.
I do the latter and have recovered over 20 pounds of solder from boards.
Glenn
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On 7/29/2018 10:51 AM, John Griessen wrote: On 07/29/2018 06:18 AM, Mark Wendt wrote:
The Hakko desoldering station I have has two sets of inline filters. One, a kind of springy thingy for stopping the solder bits and pieces from flowing into the pump, and the other a fiber disc for stopping the smokey stuff from getting through.? Perhaps on John's system the fiber disc isn't in place to stop that from happening? It's in place.? It's not enough though.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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Re: Looking for Power Cord for 400-series Scope
That's what I ended up doing. If your feet are in good condition you can
just tuck the plug end between the cord windings and it will stay put.
Paul
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On Thu, Jul 26, 2018 at 11:00:38AM -0400, n4buq wrote: I've considered cutting an IEC cord (hopefully finding a thinner version since, as you point out, the more common styles are thicker) and just using a common velcro wrap as a "keeper". The clip would be nice but having that ground connection is more important to me.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Michael A. Terrell" <mike.terrell@...>
To: [email protected]
Sent: Thursday, July 26, 2018 9:54:49 AM
Subject: Re: [TekScopes] Looking for Power Cord for 400-series Scope
They were quite common at one time. They used a thinner outer jacket to make
them more flexible. Some computer power cords are similar, and you could cut
off the IEC C13 connector.
At one time, I worked for an asset recovery company, and we sold those used
Belden cords in batches of 100 from scrapped computer terminals and other
minicomputer hardware.
Does anyone have a '70s or '80s Belden catalog to look up the specs?
Michael A. Terrell
-----Original Message-----
From: n4buq <n4buq@...>
Sent: Jul 26, 2018 8:18 AM
To: [email protected]
Subject: Re: [TekScopes] Looking for Power Cord for 400-series Scope
The manual I have shows a Belden number. I looked for that as well but no
luck.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Michael A. Terrell" <mike.terrell@...>
To: [email protected]
Sent: Wednesday, July 25, 2018 11:12:38 PM
Subject: Re: [TekScopes] Looking for Power Cord for 400-series Scope
Wasn't Tek using Belden power cords at that time?
Michael A. Terrell
!DSPAM:5b59daf7142241596617944!
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
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Re: Desoldering Iron vacuum
I also have a Metcal system, absolutely love it.
I use a $39 HF compressor for it. I bought it because it was cheaper to
buy the whole compressor from HF than individual compoenents to add on to
an existing, quieter compressor. I stuffed it into a cabinet in my bench
which makes it tolerable. That airless compressor makes a huge racket.
I like the refrig. compressor idea. One thing to keep in mind is that
many recent compressors are 3 phase and use a solid state inverter.
If you're scavenging the compressor, don't forget the inverter as well.
I ran across a good deal on Metcal power supplies and scavenged ebay for
low priced supplies, but if you like to roll your own a fellow has a
design for a Metcal power supply on eevblog. Looked quite nice.
Paul
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On Sun, Jul 29, 2018 at 07:58:50AM -0500, EricJ via Groups.Io wrote: The Metcal has a cotton or felt cube that filters this also. I'd imagine after years of use it might be wise to either clean or replace the venturi (IIRC it can be popped out and a new one slotted in). Personally I would far rather leave the system be and use it under its original guise rather than try to convert it to a vacuum only setup. Not too worried about the efficiency of the venturi generated vacuum setup as it's not used for very long time periods, just a burst for every joint. I use my "silent" compressor as an air source as well, so it comes in handy for more than just desoldering.?
I used a couple refrigerant compressors in parallel to get a little more CFM and plumbed them into a portable 5 gallon air tank with a check valve, pressure/unloading switch, regulator and filter/drier. The tank already had a pop-off valve and drain. The compressor is quiet enough to be used in my basement workshop while small children are sleeping in the bedroom directly above without waking them.
--Eric
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
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Re: Desoldering Iron vacuum
On Sun, 29 Jul 2018 09:51:22 -0500, you wrote: On 07/29/2018 06:18 AM, Mark Wendt wrote:
The Hakko desoldering station I have has two sets of inline filters. One, a kind of springy thingy for stopping the solder bits
and pieces from flowing into the pump, and the other a fiber disc for stopping the smokey stuff from getting through.? Perhaps on
John's system the fiber disc isn't in place to stop that from happening? It's in place. It's not enough though. Perhaps an automotive fuel filter? Harvey
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Re: Desoldering Iron vacuum
On 07/29/2018 06:18 AM, Mark Wendt wrote: The Hakko desoldering station I have has two sets of inline filters. One, a kind of springy thingy for stopping the solder bits and pieces from flowing into the pump, and the other a fiber disc for stopping the smokey stuff from getting through.? Perhaps on John's system the fiber disc isn't in place to stop that from happening? It's in place. It's not enough though.
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Re: Desoldering Iron vacuum
The Metcal has a cotton or felt cube that filters this also. I'd imagine after years of use it might be wise to either clean or replace the venturi (IIRC it can be popped out and a new one slotted in). Personally I would far rather leave the system be and use it under its original guise rather than try to convert it to a vacuum only setup. Not too worried about the efficiency of the venturi generated vacuum setup as it's not used for very long time periods, just a burst for every joint. I use my "silent" compressor as an air source as well, so it comes in handy for more than just desoldering.?
I used a couple refrigerant compressors in parallel to get a little more CFM and plumbed them into a portable 5 gallon air tank with a check valve, pressure/unloading switch, regulator and filter/drier. The tank already had a pop-off valve and drain. The compressor is quiet enough to be used in my basement workshop while small children are sleeping in the bedroom directly above without waking them.
--Eric
Sent from my Samsung Galaxy smartphone.
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-------- Original message --------From: Mark Wendt <wendt.mark@...> Date: 7/29/18 6:18 AM (GMT-06:00) To: [email protected] Subject: Re: [TekScopes] Desoldering Iron vacuum On 07/28/2018 08:21 PM, Ed Breya via Groups.Io wrote: John wrote
"Another thing to consider is the smoky output of desoldering. I recently repaired a Hakko 470, that has
an on-demand vacuum pump, and found the smoke had gummed up the rubber flap reed valves of the pump.
It's a good idea to have some kind of receiver container up stream of the solenoid you use, since it
would be in line to get rosin smoke. Maybe a pipe fitting container with wads of TP in it?"
Good point John. The filter wadding usually built into the desoldering head traps the chunks and some condensates, but it's inevitable that some fumes will go through the vacuum system, causing maintenance issues with heavy use.
Ed The Hakko desoldering station I have has two sets of inline filters.? One, a kind of springy thingy for stopping the solder bits and pieces from flowing into the pump, and the other a fiber disc for stopping the smokey stuff from getting through.? Perhaps on John's system the fiber disc isn't in place to stop that from happening? Mark
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I said the CRT cable (thinking of where the cable leaves the HV unit) but Harvey said it straight forward: in the vicinity of the HV unit .
This way you measure the HV transformer switching frequency (which simply is the SMPS switching frequency in the 7704A) *regardless* whether you see a dot pattern or not in the trace. The probe picks up the strong alternating EM field and not (or not in the first place) a small AC ripple on the DC HV. In self-oscillating HV situations this is a handy way to verify that the HV unit is oscillating.
You can almost sure exclude now hat there was some strange (external? oscillations?) signal entering the Z-axis amplifier causing a dot pattern since in that case you would at the same time have noticed also a running dot pattern (perhaps of different amplitude than the synchronized pattern).
Still it's not sure what causes the dot pattern, a badly decoupled LV somewhere in the Z-axis amplifier, or a badly filtered HV voltage. I would first check the Z-axis output TP41120 for 25 kHz ripple.
Just to be sure, are all shields (SMPS box and HV unit) present? I don't remember if removing the HV shield causes intensity ripple in a 7704A.
Albert
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On Sun, Jul 29, 2018 at 12:07 AM, Tomas Alori wrote:
Oh I am an idiot, I dont think you meant the CRT cable right? The CRT cable
signal would always match the dotting frequency for obvious reasons.
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Re: Desoldering Iron vacuum
On 07/28/2018 08:21 PM, Ed Breya via Groups.Io wrote: John wrote
"Another thing to consider is the smoky output of desoldering. I recently repaired a Hakko 470, that has
an on-demand vacuum pump, and found the smoke had gummed up the rubber flap reed valves of the pump.
It's a good idea to have some kind of receiver container up stream of the solenoid you use, since it
would be in line to get rosin smoke. Maybe a pipe fitting container with wads of TP in it?"
Good point John. The filter wadding usually built into the desoldering head traps the chunks and some condensates, but it's inevitable that some fumes will go through the vacuum system, causing maintenance issues with heavy use.
Ed The Hakko desoldering station I have has two sets of inline filters.? One, a kind of springy thingy for stopping the solder bits and pieces from flowing into the pump, and the other a fiber disc for stopping the smokey stuff from getting through.? Perhaps on John's system the fiber disc isn't in place to stop that from happening? Mark
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Re: Slightly OT - Bourns trimmer pot failure
The failures I saw with the Beckman pots were in telemetry receivers being built for NASA. They were the ones in use when we lost that last shuttle. The media was waiting for information, but when you had built the equipment for the earth stations, with dual diversity at every tracking site I knew as soon as they stated, We have a loss of telemetry' that we had lost another shuttle. It was like a kick in the gut, hoping for the impossible in that six complete systems had failed at the same instant instead of the loss of the shuttle.
We couldn't wait for Beckman to decide that we were right, because our products were used by many Aerospace companies where failures could cost hundreds or thousands of lives. They forced us to make the change, and only by removing a company from the master Approved Vendor List could we make sure that no one substituted anything else. Purchasing was then forced to state 'NO SUBSTITUTIONS ALLOWED ON THIS ORDER'.
As an example, a distributor offered purchasing some tighter tolerance molded inductors for a lower price than the approved part. Purchasing bought them and patted themselves on the back for sving almost 50%, but the new 5% parts caused problems that we had never had with the specified 10% parts. No one bothered to compare the SRF, and the new, unapproved vendor line was about 20% lower, across the range that we needed. Purchasing got their asses chewed out by the head of engineering and one of the Corporate VPs, over that blunder.
Michael A. Terrell
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-----Original Message----- From: Adrian <Adrian@...>
Sent: Jul 29, 2018 4:54 AM
To: [email protected]
Subject: Re: [TekScopes] Slightly OT - Bourns trimmer pot failure
Yup, you could be right, I just looked at a copy of the datasheet I
found on the web. The strap line in the sheet is "Now you can specify
Bourns for cost-sensitive applications" the sheet is marked 1977 but it
is over-stamped with "Obsolete" dated 79 so this design wasn't around
long, that may say something about the design? Certainly compared with
the lifetime of products like the 3386 which I also used in large
numbers at one point in my life with no issues.
I agree, why do people have such an issue with owning up to a problem? I
spent a fair part of my life in aerospace world and there the culture is
different - Problem? 'share early, share often' - was the mantra in
Boeing and it worked, genuine 'no blame' culture. S**t happens, what
matters is you truly understand root cause and fix it, that way we don't
kill a bunch of folks (which could include our family members, as we
were oft reminded) sitting in a tube at 35,000 ft!
On 7/29/2018 8:47 AM, M Yachad wrote:
So, crap like that happens every so often - I haven't boycotted Bourns over that - their quality is usually excellent - and it would be nice if the manufacturer would 'fess up, without dancing around an issue which is plain as day for anyone to see.
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Re: Slightly OT - Bourns trimmer pot failure
The silver was a very thin film that was applied to the substrate before the resistive element was printed on top of the substrate. The the terminals were crimped over the other end of the silver film. I saw a lot of failed foreign made versions back in the '80s where the silver had turned into black flakes that curled up and opened the pots. Just like the oxides on good silverware damage the surface with sulphates and other contaminants in the air.
See if you can uncrimp the terminal on one ind of the bad pot. Then you can see how much remains where it wasn't exposed to contaminants. It's possible that the board cleaning process started the failure mode, and it took years to finally fail.
Michael A. Terrell
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-----Original Message----- From: Adrian <Adrian@...>
Hi Michael,
You know, I've just been looking at that and you could be right, but I
*really* can't tell how those connections were made!
Comparing it with the apparently identical one on the old board I would
say there is a bit missing entirely! Without taking the second one apart
I can't be 100% sure, but it looks to have a fairly solid silvery/gold
film extending to the pcb pins that are staked through the paxolin with
what could be a varnish of some sort applied over the top. There is not
the faintest trace of anything like that on the failed part, nor the
slightest trace of any residue whatsoever, it looks like pristine
paxolin substrate with an intact resistive film applied to it and no
means of connection at all - very, very odd!
If it was open circuit all along why did things only go berserk when I
turned the pot? Floaty HF at several kV with assorted capacitors around
went unstable when screwdriver approached perhaps? Not convinced!
I have some Piher parts on the way that look like they'll fit nicely and
we'll see what happens when they arrive.
Best,
Adrian
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Re: Slightly OT - Bourns trimmer pot failure
Yup, you could be right, I just looked at a copy of the datasheet I found on the web. The strap line in the sheet is "Now you can specify Bourns for cost-sensitive applications" the sheet is marked 1977 but it is over-stamped with "Obsolete" dated 79 so this design wasn't around long, that may say something about the design? Certainly compared with the lifetime of products like the 3386 which I also used in large numbers at one point in my life with no issues.
I agree, why do people have such an issue with owning up to a problem? I spent a fair part of my life in aerospace world and there the culture is different - Problem? 'share early, share often' - was the mantra in Boeing and it worked, genuine 'no blame' culture. S**t happens, what matters is you truly understand root cause and fix it, that way we don't kill a bunch of folks (which could include our family members, as we were oft reminded) sitting in a tube at 35,000 ft!
toggle quoted message
Show quoted text
On 7/29/2018 8:47 AM, M Yachad wrote: So, crap like that happens every so often - I haven't boycotted Bourns over that - their quality is usually excellent - and it would be nice if the manufacturer would 'fess up, without dancing around an issue which is plain as day for anyone to see.
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Re: Slightly OT - Bourns trimmer pot failure
Hi Michael,
You know, I've just been looking at that and you could be right, but I *really* can't tell how those connections were made!
Comparing it with the apparently identical one on the old board I would say there is a bit missing entirely! Without taking the second one apart I can't be 100% sure, but it looks to have a fairly solid silvery/gold film extending to the pcb pins that are staked through the paxolin with what could be a varnish of some sort applied over the top. There is not the faintest trace of anything like that on the failed part, nor the slightest trace of any residue whatsoever, it looks like pristine paxolin substrate with an intact resisistive film applied to it and no means of connection at all - very, very odd!
If it was open circuit all along why did things only go berserk when I turned the pot? Floaty HF at several kV with assorted capacitors around went unstable when screwdriver approached perhaps? Not convinced!
I have some Piher parts on the way that look like they'll fit nicely and we'll see what happens when they arrive.
Best,
Adrian
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On 7/28/2018 11:32 PM, Michael A. Terrell wrote: Did that pot have a short trace of silver between the end of the resistor to the terminals?
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Re: Slightly OT - Bourns trimmer pot failure
About 6-7 years ago, I used Bourns 3352 Cermet open-frame potis as a standard for replacements on amplifiers.
I figured that open-frame would dissipate heat better.
After about 2 years, I started getting returns with amplifier failure.
Turns out that these particular 3352's had mechanical separation of the adjustable disc from the base unit.
The 3352 looks disturbingly similar to the 3555.
I'm still in contact with Bourns, trying to get some nominal type of compensation.
I switched immediately to Bourns 3386 and Piher PTC10 Cermet sealed units, and have never had a problem since.
So, crap like that happens every so often - I haven't boycotted Bourns over that - their quality is usually excellent - and it would be nice if the manufacturer would 'fess up, without dancing around an issue which is plain as day for anyone to see.
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Re: Desoldering Iron vacuum
The compressor itself sits in an oil bath, under atmospheric pressure
(the compressor shell is the inlet side), so no drain there.
You do need to drain the receiver tank, as with any compressor.
Ed is not wrong, if you _only_ need vacuum it is better to just use
the suction side directly, a venturi generator is very inefficient.
ST
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On Sat, Jul 28, 2018 at 8:31 PM, John Griessen <john@...> wrote:
How about a condensate drain valve? Do you have that to let water out the
bottom of the
compressor shell/tank? A small refrigeration compressor from a water
cooler might be a good size
for venturi vacuum generating.
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Re: Slightly OT - Bourns trimmer pot failure
I have never seen a bad Bourns trimpot that wasn't physically damaged, but I had Beckman removed from out approved vendor's list at Microdyne because they were damaged in the board cleaning process.
Beckman refused to admit a problem, but I ran a test board through the cleaning process several times and I had over a 5% failure rate. Another problem was that a slight mechanical shock would change the calibration of the circuit they were being used in.
Beckman called us about a year later and admitted that they had been using out of spec O-ring seals that allowed the citrus based cleaner to get into the pots, but by that time we had switched to Bourns for everything. It was worth the slightly higher price for much better quality.
Beckman calls themselves BI, these days.
Michael A. Terrell
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-----Original Message----- From: "petertech99h via Groups.Io" <petertech99h@...>
Sent: Jul 28, 2018 11:02 PM
To: [email protected]
Subject: Re: [TekScopes] Slightly OT - Bourns trimmer pot failure
Thank god it was not the quality enclosed Bourns pots - I use them all the time!
Replace the pot and hopefully you'll be back up and running! I don't trust open frame pots over 1M!
Cheers!
Pete
On Saturday, July 28, 2018, 6:32:24 PM EDT, Michael A. Terrell <mike.terrell@...> wrote:
Did that pot have a short trace of silver between the end of the resistor to the terminals? It can oxidize, and open. I've seen a lot of that type that failed, but they were mostly other brands. I don't like open frame pots, but they are cheap so a lot of companies used them in non-critical applications.
Michael A. Terrell
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Michael A. Terrell